Unit 3- Classification

Question 1

What is taxonomy

Answer 1

The science of classification

Question 2

What is the order of hierarchy biologists use for classification?

Answer 2

KPCOFGS (kill phill cos our family gets spicy)

Kingdoms-phyla-classes-orders-families-genera-species

Question 3

What did carolus linnaeus devise?

Answer 3

A hierarchy structure for classification in which different animals and bacteria etc were grouped into appropriate groups with no overlap
He also used this classification to devise a bionomial nomenclature (method of naming without confusion)

Question 4

How are living organisms named unambiguously/

Answer 4

Generic name (capital and comes from the genus)+ specific name (lower case and comes from the species name)

Question 5

What are the different definitions of species?

Answer 5

• morphology (need to know)
• ecological
• reproduction (need to know)
• evolutionary

Question 6

Describe the morphology species definition: and what is its flaw

Answer 6

• members of the same species have similar characteristics, such as appearance, cell structures, biochemistry (metabolic pathways)
• can be misleading as some structures arise from common ancestors (homologous structures) and some structures look similar because they arose independently to do the same job (analogous structures)

Question 7

What is the difference between an analogous and homologous structure?

Answer 7

Homologous structures look similar because they arose from a common ancestor
Analogous structures look similar but arose from different ancestors to perform the same job

Question 8

Describe the ecological definition of a species:

Answer 8

• members of the same species have the same ecological niche (role in the ecosystem), eg how it lives, feeds,competes and reproduces

Question 9

Describe the reproduction definition of a species: and pros and cons of this

Answer 9

• members of the same species can breed together in their natural environment to produce fertile offspring that cannot breed with other species
• easy to test out to see if 2 animals are the same species
• limitations are it cant be tested on extinct species and doesn’t work on asexually reproducing organisms

Question 10

Describe the evolutionary definition of a species: pros and cons of this

Answer 10

• members of the same species that share a unique common ancestor with each other and not with any other species
• can be done easily by analysing the DNA sequences of 2 different species
• some genes can be transferred across species by horizontal gene transfer

Question 11

What are phylogenetic trees?

Answer 11

Used to separate the different species to show where a common ancestor is

Question 12

How can phylogenetic trees be interpreted?

Answer 12

• going forward in time they represent speciation

- going backwards they represent the most recent common ancestor

Question 13

What 2 domains contain prokaryotes?

Answer 13

Archea and bacteria

Question 14

What is meant by the word species?

Answer 14

When 2 organisms can interbreed to produce fertile offspring they are said to be the same species

Question 15

Archea, bacteria and eukarya are the 3 domains what is different about Archea?

Answer 15

• extremophiles; they like to live in extreme conditions eg deep sea thermal vents
• they are also the nitrogen fixing and nitrifying bacteria (not technically bacteria)

Question 16

Carl Woese discovered the new domain Archea… how where is ideas critically evaluated?

Answer 16

His findings were published in scientific journals and discussed at conferences
The papers with his findings were peer reviewed and other scientists repeated his experiments to confirm and validate the findings

Question 17

What is the 3 step process used in the scientific community to ensure reliable and valid findings are presented to the public?

Answer 17

1) Peer review- the scientist must send his paper to other scientists in the same field who must agree that its Valid, Significant and original
2) published by scientific journals- any research must be published in a journal to be read by scientists
3) discussed at conferences- so scientists can discuss validity and ask questions